1. Field of the Invention
The present invention relates to a reading apparatus for reading a document at an image forming apparatus, such as a copier or the like, and more particularly to a reading apparatus readable of a photographic film.
2. Description of Related Art
Recently, a digital copier, which can read the document by an image reading apparatus and store and process an image information as an electric signal, has been popularized. Such a digital copier can easily execute positive polarization from an ordinary photographic film, in other words, a negative film, thereby obtaining a large-sized copy of a film.
In a case where the large-sized copy is thus obtained from the photographic film or the like, it is considered that, for example, a document cover provided with a reflecting plate is used to read a film image as the same as the ordinary document to thereby enlarge it by signal processing or read it by use of a magnification optical system. The film image, however, is small, thereby creating the problem in that the magnification will lower the revolving power.
Also, it is difficult to accurately position the film, and an accurate image may not be obtained. Moreover, the film as a reading object includes a slide film mounted to a slide mount and a negative film piece cut in unit of several frames, so that, when they are placed on a document table, the slide film and the film piece are different in height from each other due to thickness of the slide mount, thereby creating the problem in that resolution of either one lowers.
Accordingly, the method has been proposed which magnifies the film image on the document table by use of a projector to thereby read the magnified image (disclosed in the Japanese Patent Application Laid-Open No. 59-198439). This method, however, requires a wide space for an optical path for magnifying and projecting the film image on the document table, thereby having a defect that the apparatus becomes large-sized.